CAREER: Iron Polymerization Catalysis for the Synthesis of High Performance Degradable Polymers

在这个由化学系化学催化项目资助的项目中，Jeffery A.波士顿学院的拜尔斯正在开发方法，将玉米和大豆油等可再生原料制成的化学品转化为具有广泛特性的生物降解塑料。 这些方法基于使用催化剂来完成化学转化，并且正在开发的特定催化剂基于低毒性、地球丰富的元素铁。 这些催化剂能够制造具有新结构和组合物的塑料，这些塑料有望显示出更好的物理性能。 为了提高人们对新的可持续材料的需求的认识，并促进在STEM领域代表不足的少数民族的参与，拜尔斯教授正在开发，测试和传播一套经验演示，用于教授K-9学生科学方法以及催化和聚合物。 Byers教授还在为高中生举办“纸到塑料”研讨会，以探索如何制备可持续材料。在这个项目中，Byers教授正在研究铁的双（亚氨基）吡啶-双醇盐络合物作为催化剂，用于D，L-丙交酯和环氧化物的聚合。 当处于+2氧化态时，配合物催化D，L-丙交酯而不是环氧化物的聚合，而在+3氧化态时，配合物催化环氧化物而不是D，L-丙交酯的聚合。 因此，正在探索氧化还原化学或电化学以在两种不同的反应性模式之间切换催化剂，并且催化剂的这种性质正在用于合成环氧化物和丙交酯之间的多嵌段共聚物以及开发氧化还原触发的交联反应。 终止化学正在探索，将连接两个不断增长的聚合物链上的每个金属中心。预期这些聚合物结构改性将产生与目前使用的生物可降解聚合物相比具有独特性质的生物可降解聚合物。 该项目更广泛的影响涉及氧化还原开关在催化中介导正交反应的潜在用途，可持续材料的有用性以及计划的教育活动。

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Jeffery A. Byers of Boston College is developing methods to convert chemicals made from renewable feedstocks, such as corn and soybean oil, into biodegradable plastics with a wide range of properties. These methods are based upon using catalysts to accomplish chemical conversions, and the particular catalysts being developed are based upon a low toxicity, earth abundant element, iron. The catalysts are able to make plastics with new structures and compositions that are expected to display improved physical properties. To increase awareness of the need for new, sustainable materials and to promote the participation of under represented minorities in STEM fields, Professor Byers is developing, testing and disseminating a set of experiential demonstrations for teaching K-9 students about the scientific method as well as catalysis and polymers. Professor Byers is also working on a "Paper to Plastics" workshop experience for high school students to discover how sustainable materials can be prepared.In this project, Professor Byers is studying bis(imino)pyridine-bisalkoxide complexes of iron as catalysts for the polymerization of D,L-lactide and epoxides. While in the +2 oxidation state the complexes catalyze the polymerization D,L-lactide but not epoxides and in the +3 oxidation state the complexes catalyze the polymerization of epoxides but not D,L-lactide. Thus, redox chemistry or electrochemistry is being explored to switch the catalyst between two different modes of reactivity, and this property of the catalyst is being exploited for the synthesis of multiblock copolymers between epoxides and lactide as well as the development of a redox-triggered crosslinking reaction. Termination chemistry is being explored that will link the two growing polymer chains on each metal center. These polymer structure modifications are expected to result in biodegradable polymers with properties that are unique compared to currently used biodegradable polymers. The broader impacts of the project pertain to the potential uses of redox switching to mediate orthogonal reactivity in catalysis, the usefulness of sustainable materials, and the planned educational activities.